[WIP] tests

pkg/builder.go

@@ -250,7 +250,7 @@ func (sdb *builder) buildStateDiff(args []iterPair, params Params) ([]StateNode,
 	// these are the leafkeys for the accounts which exist at both A and B but are different
 	// this also mutates the passed in createKeys and deleteKeys, removing the intersection keys
 	// and leaving the truly created or deleted keys in place
-	updatedKeys := findIntersection(createKeys, deleteKeys)
+	updatedKeys := FindIntersection(createKeys, deleteKeys)
 
 	// build the diff nodes for the updated accounts using the mappings at both A and B
 	// as directed by the keys found as the intersection of the two

pkg/helpers.go

@@ -38,7 +38,7 @@ func sortKeys(data AccountMap) []string {
 // findIntersection finds the set of strings from both arrays that are equivalent
 // a and b must first be sorted
 // this is used to find which keys have been both "deleted" and "created" i.e. they were updated
-func findIntersection(a, b []string) []string {
+func FindIntersection(a, b []string) []string {
 	lenA := len(a)
 	lenB := len(b)
 	iOfA, iOfB := 0, 0

pkg/helpers_test.go

@@ -0,0 +1,34 @@
+package statediff_test
+
+import (
+	sd "github.com/vulcanize/eth-statediff-service/pkg"
+	"reflect"
+	"testing"
+)
+
+func TestFindIntersection(t *testing.T) {
+	// precond: a, b are sorted w/ no duplicates
+	testCases := []struct {
+		a, b, expected []string
+	}{
+		{[]string{}, []string{}, []string{}},
+		{[]string{""}, []string{""}, []string{""}},
+		{
+			[]string{"a", "b"},
+			[]string{"a", "c"},
+			[]string{"a"},
+		},
+		{
+			[]string{"a", "b", "c"},
+			[]string{"a", "b"},
+			[]string{"a", "b"},
+		},
+	}
+
+	for _, test := range testCases {
+		intersection := sd.FindIntersection(test.a, test.b)
+		if !reflect.DeepEqual(test.expected, intersection) {
+			t.Errorf("failed: TestFindIntersection\nexpected: %v\nactual %v\n", test.expected, intersection)
+		}
+	}
+}